1. Field of the Invention
The present invention relates to a novel process for producing 1,2,3-triazole compounds useful as a starting material or an intermediate of pharmaceutical products.
2. Background Art
1,2,3-Triazole compounds are useful as a starting material or an intermediate of pharmaceutical products. For example, the compounds can be utilized as an intermediate in the production of tricyclic triazolobenzoazepine derivatives which are useful as antiallergic agents as described in WO 99/16770. In a general production process of 1,2,3-triazole compounds, an acetylene compound or an olefin compound is reacted with an azide compound to cause a cycloaddition reaction and consequently to construct a 1,2,3-triazole ring (H. Wamhoff; “Comprehensive Heterocyclic Chemistry,” Pergamon Press, New York (1984), Vol. 5, p. 705).
The cycloaddition reaction of the acetylene compound with the azide compound is highly versatile, because a wide range of substituents are accepted to both the acetylene compound and the azide compound.
On the other hand, in the cycloaddition reaction of the olefin compound with the azide compound, a special olefin compound having a leaving group such as a halogen or a hydroxyl group is provided and is aromatized by an elimination reaction (H. Wamhoff; “Comprehensive Heterocyclic Chemistry,” Pergamon Press, New York (1984), Vol. 5, p. 712). The conversion to the special olefin compound is necessary for use of this cycloaddition reaction so that the production process is long. Furthermore, this cycloaddition reaction is sometimes disadvantageous in that high-temperature, high-pressure and other conditions should be used in the elimination reaction for the aromatization.
Heterocycles, vol. 51, p 481 (1999) and J. Med. Chem., vol. 26, p 714 (1983) disclose processes in which an olefin compound having no leaving group is reacted with an azide compound. This process, however, is not efficient because of low yield.
WO 99/16770 discloses a general method for converting an olefin compound to an acetylene compound. This method, however, involves a long production process and hence is cost-ineffective.
Thus, there is still a need for a process for producing a 1,2,3-triazole compound from an olefin compound having no leaving group in an efficient and cost-effective manner.